Turntable rotation with Y-axis up add-on
space_view3d_turntable_y_up.py
Enable turntable rotation with Y axis up.
space_view3d_turntable_z_up.py
Enable turntable rotation with Z axis up.    
space_view3d_turntable_any_up.py
Enable turntable rotation with any axis up, the axis that is the most vertically aligned is the up axis for the turntable rotation until a new mouse gesture, i.e. until either the mouse button or the keyboard key modiffier is released.    


All addons have the keyboard combination by default to 
Ctrl+Left Mouse Drag because there is no need to install them all.

Neither disables the built-in view rotation, so that one can have both the trackball (built-in) and the turntable (addon) at the same time mapping them to diferent keys.